The E-Sylum: Volume 7, Number 48, November 28, 2004, Article 7
LATENT HOLOGRAM AS CURRENCY SECURITY MEASURE
The following article by Mark Hartford is reprinted
from the November 25, 2004 issue of the MPC GRAM,
covering the entire World of Military Numismatics.
See papermoneyworld.net
"New anti-counterfeiting method discovered! At least
by me. Yesterday, I showed a Romanian 2,000 Lei
solar eclipse commemorative (Pick 111) to two friends
at work. They are both really smart Physics experts,
particularly in the field of visual, optics, coatings,
and infrared technologies. One noted that there was a
square in the middle of the clear window. We all
looked at it with a magnifier. One of the gentlemen
suggested that it could be a latent hologram. I asked
"what in the world is that?" He reads lots of journals
on optics and lasers, so I was surprised when he
started looking for a laser pointer used in briefings.
(Strangely, I had just bought my first laser pointer
on Saturday the 20th, in order to give my talk to
Aviation banknote talk at the IBNS meeting at the St.
Louis PCDA show.) When we found one, he pointed the
laser through this square. What was projected onto the
wall was awesome. It looks like a crescent moon with
rays emanating from the outside of it. This is clearly
the Sun with rays being occulted by the moon during a
solar eclipse. This works best in a darkened room. If
you try this, be careful not to stare directly at the
laser. I don't think staring at the reflection off of
white surfaces is very good for your eyes either. My
friend tells me that this is probably put on with a
heated metal micro-mold that contains all of the
interference patterns imbedded, so that when strong,
coherent light (i.e. a laser) transmits through it an
image is created.
I had always assumed this square was melted onto
the surface as an additional step that counterfeiters
would have to take. A minor additional task for a
counterfeiter, but still a bit of a hassle. After all,
this note catalogues for $1.50 and has a face value of
six and a half cents (ER on 25nov04 is 30,818 lei per
U.S. dollar). This is quite an advanced
anti-counterfeiting technique for such a cheap note. I
don't think making and applying these latent holograms
would be easy for counterfeiters. The low cost of
applying these (less than 6 & 1/2 cents in large
quantities) is clearly an indication that polymer
notes have yet another benefit over paper notes.
I haven't checked what other polymer notes
contain this feature. It will be fascinating to see
what other beautiful images emerge from my notes and
laser pointer in the next few days!
Hope this wasn't already known by the community,
otherwise, this is old news to everyone except me.?